Halogen-Halide Redox ReactionsAn aqueous solution of a halogen (Cl2, Br2 or I2) is poured into an aqueous halide solution (Cl-, Br- or I-) covered with a layer of hexane.

Oxidation / Reduction |

Aqueous Solution Chemistry

Gas ProducingElectrolysis of solutions with only gas(es) produced is shown.

Aqueous Solution Chemistry |

Electrochemistry |

Oxidation / Reduction

Tin CompoundsElectrolysis of tin(II) and tin(IV) solutions of different concentrations is shown.

Aqueous Solution Chemistry |

Electrochemistry |

Oxidation / Reduction

Solid ProducingElectrolysis of solutions in which a solid is produced is shown.

Aqueous Solution Chemistry |

Electrochemistry |

Oxidation / Reduction

Electrolysis of Aqueous Solutions -- NewThis is a revised version of the previously published Electrolysis of Aqueous Solutions, providing corrections and additional images. In order to understand most of these videos it is important to either see the Complete Experiment: Electrolysis of an Aqueous Solution video or to be able to read a description of that video (such as the one in the Discussion section for that video).

Electrochemical Series: Metal TreesA piece of metal (Cu, Zn, Ag, Cd, or Pb) is placed in an aqueous solution of a metal ion (Cu2+, Zn2+, Ag+, Cd2+, or Pb2+). In some cases the growth of metal crystals indicates that a chemical reaction has occurred.

Precipitation ReactionsApproximately 2 mL of Solution A is added to a sample of Solution B with a dropping pipet. If a precipitate forms, the resulting precipitate is supended in the mixture. The mixture is then stirred with a glass stirring rod and the precipitate is allowed to settle for about a minute.

Exploding Soap Bubbles: Hydrogen + OxygenA series of three videos shows that as the ratio of oxygen to hydrogen in soap bubbles increases, the explosions that occur when the bubbles are ignited get louder. (The fact that with an excess of oxygen the explosions would become softer again is not shown.) Each video is repeated with no voice-over so that only the sounds of the explosions are heard. Five still images are provided to show the stoichiometry on the molecular scale. The videos are intended to be shown in order beginning with Hydrogen Alone and ending with hydrogen plus more oxygen.

Electrolysis of several aqueous solutions is carried out using a 9-V battery and pencil leads as electrodes. Because only the electrodes are shown in the videos, it is important to show these still images

or describe how the reactions were performed if students are to make sense of the videos. In each case the anode is on the left and a 9-V battery has been connected to the lead of each of the pencils near the eraser end with an alligator clip.

Oxidation-Reduction ReactionsElectrolysis reactions and the action of nitric acid on iron and copper illustrate the concepts of oxidation and reduction. Also three oxidation-reduction reactions are shown under a microscope.

Formation of Carbon from CarbohydrateSulfuric acid has a very high affinity for water. It is shown to dehydrate a carbohydrate (sucrose) forming carbon. Sulfuric acid is reduced to sulfur dioxide, which bleaches a rose petal.
In a second experiment, the sulfur dioxide reduces purple permanganate to nearly colorless manganese(II).

Acids / Bases |

Carbohydrates |

Oxidation / Reduction |

Reactions

SolutionsReactions and demonstrations exploring the concepts of solutions.

Pulsating Electrochemical Reaction: Mercury Beating HeartA drop of mercury in a watch glass is covered with a solution of potassium chromate in concentrated sulfuric acid. An iron nail is positioned so that it nearly touches the mercury. Eventually, the mercury drop starts to beat rhythmically, like a beating heart.

Ammonia Fountains - MultipleSystem of multiple ammonia fountains are set up and run. A separatory funnel, four round-bottomed flasks, and some tubing form a closed system. One end of the tubing is immersed in an acetic acid solution that contains universal indicator. The glassware has been filled with ammonia gas. The stopcock of the funnel is closed.

Iodine Clock ReactionA solution of hydrogen peroxide and sulfuric acid is added to a solution containing iodide ion, thiosulfate ion, and starch. After some time the dark blue color of a triiodide-starch complex is observed. The influences of initial reactant concentrations on the reaction time are examined, as are the influence of volume and temperature.

Blue Bottle, Red and Blue BottleColor changes are caused by reactions of oxygen in the air with chemicals in a solution. The colors fade over time, but can be regenerated by shaking the flask containing the solution.

Oscillating Reaction: Briggs-RauscherWhen a solution of malonic acid, starch, and manganese(II) ion is added to a solution of hydrogen peroxide, iodate ion, and sulfuric acid, gas bubbles form and the color of the resulting mixture oscillates periodically from colorless to amber to blue.

Orange Juice ClockIn this demonstration a galvanic cell is made from the combination of a magnesium strip, a copper strip, and juice in a beaker. The current from this cell is used to drive a clock normally powered by a DC battery.

Reactions, Microscale: PrecipitationHere we show two precipitation reactions under a microscope. They are potassium dichromate crystal with silver nitrate and potassium iodide with lead nitrate.

Precipitation / Solubility |

Reactions

Reaction, Microscale: Potassium Dichromate with Silver NitrateA crystal of potassium dichromate is carefully combined with a solution of silver nitrate under a microscope. The reaction takes some time, so it is shown in a series of seven sequential videos. To see the entire reaction you need to play all seven.

Combustion of MethaneMethane combustion in balloons, a Bunsen burner flame, and methane combustion in chlorine are demonstrated.

Alkanes / Cycloalkanes |

Reactions

Combustion of HexaneCombustion of hexane with limited oxygen and addition of water to burning hexane are demonstrated.

Alkanes / Cycloalkanes |

Reactions

Bromination of HydrocarbonsThe light initiated bromination of pentane, hexane isomers, alkyl benzenes and a comparison of bromination of pentane and pentene are demonstrated.

Alkanes / Cycloalkanes |

Reactions

Diels-Alder VisualizationSeveral computer animations of a Diels-Alder reaction that were created as an undergraduate student project are presented.

Addition Reactions |

Alkenes

Addition Reactions of AlkenesThe Diels-Alder reaction, addition of oxygen to tetrakis(N, N-dimethylamino) ethylene, polymerization of ethylene, and addition of iodine to a-pinene are demonstrated. Molecular models of ethene are shown.

Hydrogen + Chlorine CannonWhen a corked test tube containing a mixture of hydrogen and chlorine is struck by light from a burning magnesium ribbon, the resulting explosion propels the cork out of the test tube.

Gases |

Photochemistry |

Reactions

HydrogenReactions and explosions involving hydrogen and its compounds are demonstrated.

Reactions |

Descriptive Chemistry

OxygenReactions and explosions involving oxygen and its compounds are demonstrated.

Reactions of Sulfurous AcidThese demonstrations illustrate the production and effects of sulfur dioxide, a pollutant generated by the burning of sulfur impurities in coal. The sulfurous acid produced by dissolving sulfur dioxide in water is allowed to react with various forms of calcium carbonate found in nature, namely marble, limestone, chalk, and eggshell.

Acids / Bases |

Precipitation / Solubility |

Reactions

Reactions of Nitric AcidThese demonstrations illustrate the production of nitric acid and its reaction with various forms of calcium carbonate found in nature, namely marble, limestone, chalk, and eggshell.